For this being your first game ever and your first game jam this is super impressive! My first game using Gdevelop was for a game jam too and I didn't even finish it despite having more time than you. I couldn't even imagine adding cutscenes at the time but you pulled it off somehow. Good job!
I see that a few people already brought up my critiques, i.e. lacking a little game feel, inconsistent art between each sprite, and a floaty jump. I know that a game made in 48 hours isn't going to be perfect but I wanted to reiterate those points because I'd love to see you grow